DOCFIX-175/176: OpenTofu state file security + VR1 teardown/rollback runbook ...

Found while reviewing what's missing from the VR1 buildout ahead of
tomorrow's execution.

DOCFIX-175: terraform.tfstate stores sensitive=true variables (like
maas_api_key) in plaintext regardless of the flag, which only redacts
CLI/plan output (verified against HashiCorp's own docs). Added .gitignore
coverage, a "State file handling" section in opentofu/README.md, an inline
caveat on maas_api_key's description, and a "SECURE THE STATE FILE" callout
at Stage 1 Step 10 -- the actual first real tofu apply (an early draft
wrongly assumed Stage 3; corrected after reading the runbooks directly).

DOCFIX-176: new runbooks/dc-dc-teardown-rollback.md for the OpenTofu/
libvirt/MAAS-vm_host layer, which D-061's existing teardown scripts don't
cover (different layer, juju/MAAS-machine). Two paths (scoped -target
teardown or full VR1 destroy), a rollback decision tree favoring
fix-forward over destroy, and explicit mesh-link shared-infrastructure
handling.

Also folded in: a fix to docs/changelog-20260710-ledger-scan-self-inflicted-falsepositive-fix.md
after re-running ledger-scan.sh caught that its own narration (and the
session-ledger mirror) had reintroduced the exact false-positive class
DOCFIX-174 had just fixed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QrcJx8TUar7pYAvpGJw57A

DOCFIX-147: opentofu/modules/maas-vm-host + modules/netem-link ...

Registers the vcloud host with MAAS as a virsh VM host, and applies tc netem
WAN-simulation parameters -- the two remaining unbuilt mechanisms from the
OpenTofu scope, researched before drafting per instruction.

maas-vm-host uses canonical/maas's maas_vm_host (register the chassis so
MAAS discovers already-existing VMs), deliberately not maas_vm_host_machine
(composes new VMs itself -- takes cores/memory/disks as inputs). Read both
schemas and cross-checked against D-103's explicit "MAAS does NOT compose
new ones" before picking one.

netem-link uses terraform_data (OpenTofu's own recommended replacement for
null_resource) with an SSH-wrapped local-exec provisioner -- confirmed
local-exec runs on the machine invoking tofu apply (Office1 per D-103), not
the vcloud host where the bridges live, so a bare local command would do
nothing useful.

Neither module instantiated: needs a real MAAS zone/pool, the vcloud host's
SSH target, and real netem parameters, none of which exist yet.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QrcJx8TUar7pYAvpGJw57A

DOCFIX-142: opentofu/ network + storage-pool scaffold (VR1 IaC, gap #2) ...

First OpenTofu content in the repo. Network/pool layer only: modules/dc-planes
(the six per-DC planes, D-052/D-100), modules/mesh-link (the D-100 dark-fiber
triangle), modules/dc-storage-pool, wired for DC1 (inherits DC0's CIDRs per
D-101) and Office1. DC2 deliberately not wired -- its CIDRs aren't assigned
yet (D-101 open sub-item).

Provider schema (dmacvicar/libvirt v0.9.8) verified against its actual current
docs this session, not memory -- it has diverged materially from older common
examples (network isolation is a nested forward.mode, not top-level mode;
libvirt_domain restructured to ~40 args mirroring raw libvirt XML). Node-VM/
volume resources, OPNsense config, and tc netem application are deliberately
deferred: that schema is too large/unfamiliar to author safely without a real
`tofu providers schema` pass on a connected machine -- see opentofu/README.md
for the full account and the concrete next step.

Added scripts/opentofu-validate.sh (fmt/init/validate wrapper) + a harness
testing what's actually exercisable without a tofu binary (none is available
anywhere this repo has been worked in this session -- logged, not hidden).
Extended repo_lint.py's L1 check to cover .tf files (uncovered before since
none existed). repo-lint 0 fail / 1 documented warn; both harnesses green.
Workflow doc + its companion visual tracker updated to match.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QrcJx8TUar7pYAvpGJw57A